diff --git a/README b/README
index a8cd199..a8552bf 100644
--- a/README
+++ b/README
@@ -86,6 +86,9 @@
         * oftest checked out (called <oftest> here)
         * scapy installed:  http://www.secdev.org/projects/scapy/
           'sudo apt-get install scapy' should work on Debian.
+        * pypcap installed:  http://code.google.com/p/pypcap/ (optional)
+          'sudo apt-get install python-pypcap' should work on Debian.
+          Tests using VLAN tags may fail without pypcap.
         * tcpdump installed (optional, but scapy will complain if it's
           not there)
         * Doxygen and doxypy for document generation (optional)
@@ -248,6 +251,9 @@
     fields in the packets.  With the local platform, you can use wireshark
     on the loopback interface as well as the dataplane veth interfaces.
 
+    3.  If tests dealing with VLANs fail unexpectedly then try installing
+    pypcap (see Longer Start above).
+
 Adding Your Own Test Cases
 ++++++++++++++++++++++++++